Radio alarm for parking meters



May 17, 1960 R. E. MILLER RADIO ALARM FOR PARKING METERS 2 Sheets-Sheet 1 Filed Jan. 16, 1959 RAY E, MILLER.

INVENTOR FIG. I

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United States PatentfO 2,937,269 I RADIO ALARM FOR PARKING METERS Ray E. Miller, Portland, reg., assignor of twelve and one-half percent to James D. Givnan and twelve and one-half percent to James D. Givnau, In, both of Portland, Oreg.

- Application January 16, 1959, Serial No. 787,234 4 Claims. (Cl. 250-17) quently a matching transformer or similar device. These components make installations diflicult where space requirements are important.

Accordingly, one of the principal objects of the invention is to provide a radio transmitter of the character described which is small and compact, adapted for mounting and concealment within a metallic housing whose inside transverse dimensions are substantially the same as the external dimensions of the radio transmitter itself and wherein the housing provides the required'low impedance heretofore provided, to the best of my knowledge, only by antenna systems and equipment above referred to.

These unique characteristics of my radio transmitter render it adaptable to such a profusion of uses that enu- I meration is thought superfluous. However, and without prescribing any limits of utility, I have herein shown and described the transmitter in combination with a parking meter, also made in accordance with the invention, and wherein the standpipe of the meter provides the antenna for the transmitter encased within the standpipe and adapted to transmit coded alarm signals when the meter is tampered with by an unauthorized person in an attempt to force open the coin box in the-meter head.

A further object of the invention is to provide a coding device within each parking meter to indicate through a stepping switch and drop target, located, for example, at a police station or in police prowl cars, the location of a series of meters or the location of any particular meter in a series.

2,937,269 Patented May 17, 1960 2 to put the alarm system in operation, and a manual switch for deenergizing the system. f

Figure 4 is a fragmentary sectional'view on an errlarged scale of the hollow supporting standard for the meter head and showing the mounting on the interior thereof of the radio signal transmitter of this invention: 1 Figure 5 is a top plan view of Figure 4 with a frag ment' broken away and some parts omitted for clearness of illustration. I

Figure 6 is a wiring diagram of the electrical circuits of the radio signal transmitter including the coding device which is shown diagrammatically.

With continuing reference to the drawings, wherein references of character designate like parts, and with particular reference to Figures 1-4, reference numeral 1 indicates a hollow standard mounted upon a base 2 adapted for securement to asidewalk in any approved manner adjacent the curbstone thereof. A meter head, indicated generally'at 3, is secured in the conventional manner to the top end of the standard 1. 7

The meter head is divided by a partition 4 into an upper compartment 5 for the meter mechanism (not shown) and a lower compartment 6 for the reception of coins inserted in the coin slot 7 or for a coin box (not shown) to receive the coins so inserted. The upper compartment 5 is provided with an access doors, and the bottom compartment 6 is provided with an access door 9. The doors 8 and 9 are provided with locking mechanisms 10 and 11 respectively operable only by keys carried by authorized persons employed to service the meters and to collect the coins therefrom. A normally closed, manually' actuated switch 12 is mounted upon the partition 4 and is accessiblewhen the door 8 is open. A normally open micro switch 13 is secured to the underside of the partition 4 within the coin compartment 6 and is operable from an open to a closed position by the initial outward swing of the door 9 to thereby complete the electrical circuit to energize the transmitter and coding device, as will be hereinafter pointed out in the description of the wiring diagram shown in Figure 6.

V In Figures 4 and 5 reference numeral 15 indicates a hollow cylinder open at its bottom end and flanged inwardly as at 16 at its top end. These end portions of a friction fit within the cylinder 15 is a radio chassis in A still further object of the invention is to provide within the meter head a switch whose location is known only to an authorized collector of the coins, to enable him to open or close the coin box without electrically energizing the alarm system.

The foregoing and other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawing forming a part hereof and in which:- 4

Figure 1 is a front elevational view of a parking meter having a head with an access door to the mechanical mechanism therein and a second access door to the money compartment or coin box compartment.

Figure 2 is a side elevational view-of the meter head shown in Figure l with both access doors shown in open positions by broken lines. I

Figure 3 is a fragmentary view on an enlarged scale similar to Figure 2 showing both access doors closed, a micro switch operable from an open to a closed position the form of a housing 18 flanged inwardly along both of its sides as at 19 and 20. The upper flanges are interconnected by straps 21 to which an A' battery 23 is attached by a spring clip 22. Two B batteries 24 and 25 are mounted within the upper end of the housing. Mounted upon a platform 25 secured transversely to the bottom end of the upper flanges is a crystal 26, radio tube socket 27, and radio tube 28. Attached to and depending from the underside, of the platform are a grid choke 29 and a grid bias resistor 30.

Secured within the lower part of the chassis 18, by means of the flanges 19 and 20 thereof, is a panel 35 of dielectric material. An arm 36 of the same material, secured as at 37 to the panel, extends downwardly therefrom and is provided with a slidable clip 38 integrated with or secured to spring fingers 39 in contact with the inner walls of the standard 1. These fingers are vertically adjustable and lockable in adjusted positions by a bolt 40 extending through the clip 38 and a slot 41 and provided with a lock nut 42.

bythe initial outward swingof the door of the coin box Attached to the rear face of the panel 35 in the same manner as the A battery 23 is a second A battery 45. Secured by its base 46 to the rear face of the panel 35 (see Figure 5) is a coding device comprising a low voltage motor 47 secured to the base and having one end of its shaft 48 journaled in a bearing 49 also secured to the base. Secured to the motor shaft for rotation therewith (see also Figure 6) is a cam wheel 50 having a single lobe 51, and a pulsing cam wheel 52 having a plurality of lobes 53 matching in number the identification number applied to one parking meter of a series. For example, the pulsing cam wheel with the five lobes as shown could be applied to the fifth meter to indicate its location in a series of meters, or the same pulsing cam could be applied to all meters in a series identified by the numeral 5.

With particular reference to Figure 6, the radio transmitter comprises the radio tube 28, grid circuit 60, the crystal 26, a plate circuit indicated general-1y at 61 and including a variable condenser 62 and tuning coil 63, all electrically interconnected in the conventional manner.

For intermittently making and breaking the electrical circuit to thev radio transmitter, I provide a pulsing switch comprising a switch arm 65 provided with a movable contact 66 near the outer end and in the path of rotation of the lobes 53 on the pulsing cam wheel 52 and thereby adapted to be put into and out of contact with a fixed contact 67 connected by wire 68 to one side of the transmitter circuit. The movable contact 66 is connected by conductor 69 to the negative side of the B battery 24 whose positive side is connected as at 70 to the negative side of B battery 25 whose positive side is connected by conductor 71 to the other side of the transmitter circuit through a choke coil 72. Accordingly, five signals will be sent out by the transmitter during each revolution of the pulsing cam wheel 52 and these signals will be picked up by a receiver (not shown) adapted to operate a stepping switch located, for example, at a police station and adapted to drop a target corresponding'in number with the number of signals, which in this instance would be five.

One side of the A battery 45 is connected by conductor 80 to one side of the motor 47 whose opposite side is connected by Wires 81 and 82 to one side of the normally open micro switch 13 within the coin compartment 6 of the meter head. The opposite side of switch 13 is connected as at 83 to one side of the normally closed manual switch 12 whose opposite side is connected by wire 84 to a fixed contact 85 cooperating with a movable contact 86 carried by a switch arm 87 and connected by conductor 88 to the other side of the A battery 45. Movable contact 86 also cooperates with a second fixed contact '90 connected as at 91 to wire 82 and thereby to the said one side of the normally open micro switch 13.

From the foregoing it will be apparent that when switch 13 is closed by the opening of door 9 to the coin compartment and with switch arm 86 in the position shown, current will flow from A battery 45 through conductor 88, wire 84-, both switches 12-13, and wires 82 and 81 to one side of the motor and from the other side thereof through wire 80 back to the A battery 45. The instant the motor and cam wheel 50 are put into operation in a clockwise direction as viewed in Figure 6, the switch arm 87 will drop from the lobe 51 to thereby break contact between 86 and 85 and make contact between 86 and 90, which will close the circuit from the A battery 45 through conductor 88, wires 91, 82 and '81 to one side of the motor and from the other side thereof through wire 80 back to the battery. The cam wheel 50 will then be rotated one revolution until the lobe 51 lifts the switch arm 87 and breaks contact between 90 and 86. During this one revolution of the cam Wheel 58 and hence the cam wheel 52, the five lobes 53 will intermittently make and break the circuit from one side of the B battery 24 through wire 69, contacts 6'766, wire 68, through the negative side of the radio tube 28 and the circuit from the negative side of B battery 24 to the negative connection 101 of the radio tube. a

The resultant oscillation produced in the plate tank circuit (condenser 62 and inductance 63) is transmit-ted into the coupling circuit through a coupling coil 104, variable condenser 105, adjustable spring contacts 39, through the pipe standard 1 from the contacts 39 to a fixed contact 106 (see also Figure 4). The length of pipe between contacts 39 and 186 thus becomes the low impedance part of the antenna and these antenna connections work most favorably at a frequency as near the physical dimensions of the pipe as possible.

From the foregoing it will be seen that I have provided a radio transmitter and housing therefor wherein the housing provides the antenna. Although I have shown and described the housing as a pipe in the present embodiment of the invention, it will be readily understood that metallic housings of other shapes and sizes may be utilized just as effectivelybecause of the adjustable,

relationship between the spring contacts 39 and fixed contact 106.

While I have shown a particular form of embodiment of my invention, 1 am aware that many minor changes therein will readily suggest themselves to others skilled in the art without departing from the spirit and scope of the invention. Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. A radio transmitter and antenna therefor, comprising in combination a housing, a chassis carrying a radio transmitter and adapted for removable mounting within said housing, said radio transmitter including a coupling circuit including a fixed contact and a movable contact, and a plate tank circuit adapted to transmit oscillations into said coupling circuit, said fixed contact carried by said chassis and in contact with said housing, said movable contact carried by the chassis and adapted for selective contact with said housing at points remote from said fixed contact whereby the length of housing between said fixed and movable contacts becomes the low impedance part of said antenna.

2. A radio transmitter and antenna therefor, comprising in combination an elongated tubular metal housing, a chassis carrying a radio transmitter and adapted for removable mounting within said housing, said radio trans mitter including a coupling circuit including a fixed contact and a movable contact, and a plate tank circuit adapted to transmit oscillations into said coupling circuit, said fixed contact carried by said chassis and in contact with said housing at one end thereof, said movable contact carried by the chassis and adapted for selective contact with said housing at points remote from said fixed contact whereby the length of housing between said fixed and movable contacts becomes the low impedance part of said antenna.

3. A radio transmitter and antenna therefor, comprising in combination an elongated tubular metallic housing, a receptacle mounted on one end of said housing, a closure for the receptacle, a normally open switch within the receptacle, and operable into a closed position by the opening of said closure, a chassis carrying a radio transmitter and -a source of electrical energy in circuit with said switch and said radio transmitter, said chassis adapted for removable mounting within said housing, said transmitter including a coupling circuit including a fixed contact and a movable contact and a plate tank circuit adapted to transmit oscillations into said coupling circuit, said fixed contact carried by said chassis and in contact with said housing at one end thereof, said movable contact carried by the chassis and adapted for selective contact with said housing at points remote-from said fixed contact whereby the length of housing between said fixed and movable contacts becomes the low impedance part of said antenna when the radio transmitter is energized by the closing of said switch.

4. A radio transmitter and antenna therefor, comprising in combination an elongated tubular metallic housing, a receptacle mounted on one end of said housing, aclosure for the receptacle, a normally open switch within the receptacle and operable into a closed position by the opening of said closure, a chassis carrying a radio transmitter and a source of electrical energy in circuit with said switch and said radio transmitter, an electric motor and a source of electrical energy therefor carried by the chassis, said motor being in circuit with said switch, a coding cam operable by said motor, cooperating contacts in the radio transmitter circuit operable by the coding cam for intermittently energizing the radio transmitter, said radio transmitter including a coupling cir- 'cuit including a fixed contact and a movable contact and a plate tank circuit adapted to transmit oscillations into said coupling circuit, said fixed contact carried by said chassis and in contact with said housing at one end thereof, said movable contact carried by the chassis and adapted for selective contact with said housing at points remote from said fixed contact whereby the length of housing between said fixed and movable contacts becomes No references cited. 

